```
This PR builds on PR #16702 to add functional tests / sanity checks and
user-facing refinements for passing -asmap to configure ASN-based IP
bucketing in addrman. As per our review discussion in that PR, the idea
here is to handle aspects like functional tests and config arg handling
that can help the PR be merged while enabling the author to focus on the
bucketing itself.
```
Backport of core PR17812.
Depends on D8198.